The protein antigens exposed on the surface of the outer membrane of Neisseria gonorrhoeae responsible for conferring strain and species specificity will be determined by the use of highly specific antibodies produced by somatic cell fusion. These monoclonal antibodies elaborated by murine hybridomas will provide an excellent source of reagents for study of the protein antigens of the gonococcus. These antobodies will be used to prepare immunoaffinity columns to purify the outer membrane proteins of the gonococcus. Both purified antigens and antibodies will subsequently be used to develop assays for monitoring immune response in human sera to gonococcal surface proteins, for determination of antigens in clinical isolates and for quantitating antigens in a gonococcal cell population.